The study seeks to determine whether oral magnesium supplementation may prevent cell dehydration and impede red cell K loss in normal volunteers and HbSS individuals. Prevention of red cell K loss and dehydration is one of the possible therapeutic strategies for sickle cell anemia. Objectives: 1) The study aims to evaluate the effect on erythrocytes and the toxicity of oral magnesium supplementation in normal volunteers. 2) To determine if oral Magnesium supplementation in sickle cell patients leads to increased cell Magnesium content, inhibition of red cell dehydration and reduced sickling.